///*
// * Licensed to the Apache Software Foundation (ASF) under one or more
// * contributor license agreements.  See the NOTICE file distributed with
// * this work for additional information regarding copyright ownership.
// * The ASF licenses this file to You under the Apache License, Version 2.0
// * (the "License"); you may not use this file except in compliance with
// * the License.  You may obtain a copy of the License at
// *
// *    http://www.apache.org/licenses/LICENSE-2.0
// *
// * Unless required by applicable law or agreed to in writing, software
// * distributed under the License is distributed on an "AS IS" BASIS,
// * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// * See the License for the specific language governing permissions and
// * limitations under the License.
// */
//
//package com.boonya.spark.examples.ml;
//
//import org.apache.spark.sql.Dataset;
//import org.apache.spark.sql.SparkSession;
//
//// $example on$
//import java.util.Arrays;
//import java.util.List;
//
//import org.apache.spark.ml.feature.VarianceThresholdSelector;
//import org.apache.spark.ml.linalg.VectorUDT;
//import org.apache.spark.ml.linalg.Vectors;
//import org.apache.spark.sql.Row;
//import org.apache.spark.sql.RowFactory;
//import org.apache.spark.sql.types.*;
//// $example off$
//
///**
// * An example for VarianceThresholdSelector.
// * Run with
// * <pre>
// * bin/run-example ml.JavaVarianceThresholdSelectorExample
// * </pre>
// */
//public class JavaVarianceThresholdSelectorExample {
//  public static void main(String[] args) {
//    SparkSession spark = SparkSession
//      .builder()
//      .appName("JavaVarianceThresholdSelectorExample")
//      .getOrCreate();
//
//    // $example on$
//    List<Row> data = Arrays.asList(
//      RowFactory.create(1, Vectors.dense(6.0, 7.0, 0.0, 7.0, 6.0, 0.0)),
//      RowFactory.create(2, Vectors.dense(0.0, 9.0, 6.0, 0.0, 5.0, 9.0)),
//      RowFactory.create(3, Vectors.dense(0.0, 9.0, 3.0, 0.0, 5.0, 5.0)),
//      RowFactory.create(4, Vectors.dense(0.0, 9.0, 8.0, 5.0, 6.0, 4.0)),
//      RowFactory.create(5, Vectors.dense(8.0, 9.0, 6.0, 5.0, 4.0, 4.0)),
//      RowFactory.create(6, Vectors.dense(8.0, 9.0, 6.0, 0.0, 0.0, 0.0))
//    );
//    StructType schema = new StructType(new StructField[]{
//      new StructField("id", DataTypes.IntegerType, false, Metadata.empty()),
//      new StructField("features", new VectorUDT(), false, Metadata.empty())
//    });
//
//    Dataset<Row> df = spark.createDataFrame(data, schema);
//
//    VarianceThresholdSelector selector = new VarianceThresholdSelector()
//      .setVarianceThreshold(8.0)
//      .setFeaturesCol("features")
//      .setOutputCol("selectedFeatures");
//
//    Dataset<Row> result = selector.fit(df).transform(df);
//
//    System.out.println("Output: Features with variance lower than "
//        + selector.getVarianceThreshold() + " are removed.");
//    result.show();
//
//    // $example off$
//    spark.stop();
//  }
//}
